The strike meant the first day of the new school year in Columbus City Schools — Ohio’s largest school district — was held online, with substitutes leading virtual classes Wednesday while 4,500 teachers, librarians, counselors and other school workers were on strike . The strike comes as schools across the country face critical teacher shortages and low morale among teachers, who say they are underpaid and underpaid, teaching in overcrowded classrooms and in difficult conditions exacerbated by the pandemic. Teachers in Columbus were demanding 8 percent annual pay raises, as well as commitments to improve heating and air conditioning in dilapidated buildings, smaller class sizes and full-time elementary school art, music and physical education teachers. The new agreement includes provisions guaranteeing that all student learning areas will be climate-controlled by the start of the 2025-2026 academic year, reduced class sizes in all grades and a paid parental leave program for teachers, as well as and salary increases for the next three years, Fuentes said. The district had previously offered a 3 percent pay raise but denied guaranteed air conditioning — an issue at the heart of the strike, according to the union. Thousands of people attended the tracks last week, many holding signs citing problems with temperatures in schools. “98 DEGREES IS A SHOPPING BAND NOT A CLASSROOM TEMPERATURE,” read a sign held by a teacher outside East High School. After the agreement was reached early Thursday after a nearly 14-hour negotiating session, teachers used Thursday and Friday to plan to prepare to return to the classroom on Monday. “We are excited to be back where we belong — our classrooms — doing what we do best: educating our students and shaping the future of our great city,” Fuentes said. Fuentes added that workers across the nation are “tired of settling for the status quo” and said she hopes the union’s work is a catalyst that will inspire people nationwide to fix problems in public education. “They need to invest more in our students because they are the most important investment in the entire nation,” Fuentes said. “It’s starting here, but we want to keep it going. Hopefully the community will see what power it has and get even more involved.” Officials at Columbus City Schools, which serve 47,000 students, said the new agreement puts children first. “This is a contract that keeps students at the center of everything we do and supports our board’s educational mission for Columbus City Schools,” Board of Education President Jennifer Adair said in a statement Sunday. “To all CEA members, we say thank you for your careful consideration of this agreement and for your unwavering commitment to supporting our children and families. We look forward to bringing our children back to their schools with you tomorrow.” CNN’s Nouran Salahieh contributed to this report.